It is shown in European Patent Application No. 0 354 660 to manufacture nozzles, in the form of orifice plates, which represent "S-type" plates. Therefore the inlet and outlet openings in the orifice plate are configured at an offset to one another, thus necessarily creating an "S-bend" in the flow of a fluid flowing through the orifice plate. The proposed orifice plates are constituted by two flat platelets made of silicon and assembled together by bonding. Regions of reduced thickness are shaped out of the silicon platelets so that shear gaps are formed parallel to the end surfaces of the platelets between the openings of the first platelet and the one opening of the second platelet. The inlet and outlet openings are manufactured with the known mask method by etching onto silicon wafers that possess a plurality of orifice plate structures. The troncoconical contours for the openings in the orifice plate result logically from the anisotropic etching technique.
A valve arrangement consisting of an elastic silicon valve platelet and a nozzle platelet, also made of silicon, is already known from EP-OS 0 314 285. The two silicon platelets are joined to one another and can be deflected relative to one another. Inlet openings that are arranged at an offset from outlet openings in the nozzle platelet are provided in the silicon valve platelet. With the valve arrangement in the closed state, plateau surfaces of the silicon valve platelet seal off the outlet openings in the nozzle platelet, while when the nozzle platelet is bent by means of an actuation member, an S-shaped passage for a fluid is created and the valve arrangement is open.
A fuel injection valve that has at its downstream end a nozzle consisting of two silicon platelets is already known from U.S. Pat. No. 4,907,748. Similarly to the orifice plates described above, the inlet and outlet openings in the two silicon platelets have offsets to one another, resulting in an "S-bend" in the flow of a fluid, in this case fuel, as it flows through.
All the aforementioned orifice plates made of silicon have the disadvantage of possibly insufficient fracture resistance, resulting from the brittleness of silicon. There is a risk, specifically under continuous loads, for example on an injection valve (engine vibrations), that the silicon platelets will break. Mounting the silicon platelets to metallic components, for example to injection valves, is difficult, since special stress-free clamping solutions must be found and sealing on the valve is problematic. It is impossible, for example, to weld the silicon orifice plates to the injection valve. Moreover there is the disadvantage of edge wear on the openings of the silicon plates as a fluid repeatedly flows through them.
Also already known, from German Patent No. 483 615, is a nozzle for fuel-injected internal combustion engines that is also constituted by two nozzle platelets, the nozzle platelets having inlet and outlet openings, arranged at an offset to one another, in order to promote disaggregation of the fuel flowing through. With this nozzle, however, it is in no way possible to shape the injected fuel in accordance with a desired geometry. The two metal nozzle platelets are manufactured and machined by conventional technology (stamping, pressing, rolling, cutting, drilling, milling, grinding, etc.).